Synthesis 2022; 54(18): 3941-3961
DOI: 10.1055/s-0040-1719930
short review

Recent Advances in Transition-Metal-Catalyzed Reactions of N-Tosylhydrazones

V. Vaishya
,
R. Singhal
,
T. Kriplani
,
M. Pilania


Abstract

N-Tosylhydrazones are highly versatile precursors for in situ carbene formation and are frequently used in metal-catalyzed cross-coupling reactions. Due to their many applications in organic synthesis, including C–C, C–O, C–N, and C–S bond formation, N-tosylhydrazones have recently received much interest. They can be simply synthesized by reacting an aldehyde or ketone with N-tosylhydrazine to produce a solid N-tosylhydrazone, which is a ‘green’ precursor of diazo compounds. Using a suitable metal catalyst, N-tosylhydrazones show versatile substrate scope for the synthesis of substituted diaminopyrroles, chromenopyrazoles, alkenylpyrazoles, benzofuran thioethers, tetrahydropyridazines, sulfur-containing heterocycles, and benzofurans with potent biological activities and even regioselective N-functionalization reactions. Metal-catalyzed reactions of N-tosylhydrazones for the construction of bioactive heterocycles are still highly in demand. Hence, this review focuses on the recent synthetic application of N-tosylhydrazones influenced by different transition metals with notable features like simple workup procedures, gram-scale synthesis, broad substrate scope, multicomponent processes, cyclization, and carbon–heteroatom bond formation.

1 Introduction

2 Applications of N-Tosylhydrazones

3 Conclusion



Publication History

Received: 15 April 2022

Accepted: 26 April 2022

Article published online:
30 June 2022

© 2022. Thieme. All rights reserved

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany